Imidazoles are useful as chemical intermediates, for example they are used in the preparation of pharmaceuticals and pesticides. Commercially they are typically made by the condensation of a glyoxal, aldehyde ammonia and optionally an amine, depending on the substituents desired on the imidazole ring, see for example E. Elvers., et al., Ed., Ullmann's Encyclopedia of Industrial Chemistry, 5.sup.th Ed., Vol. A13, VCH Verlagsgesellschaft mbH, Weinheim, 1989, p. 661-668; M. R. Grimmett in K. T. Potts, Ed., Comprehensive Heterocyclic Chemistry, Vol. 5, Part 4A, Pergamon Press, New York, 1984, p. 482-486; and M. R. Grimmett, Adv. Heterocycl. Chem., Vol. 12, p. 105-117 (1970). However, these condensations often do not give high yields of the desired products, especially when a particular substituted imidazole is desired. Therefore improved syntheses of imidazoles are desired.
As reported in M. R. Grimmett, Adv. Heterocycl. Chem., Vol. 12, p. 1 (1970), formaldehyde and ammonium carbonate, when exposed to actinic radiation having a wavelength of 254 .mu.m, yields a mixture of imidazole, 4-methylimidazole and 4-hydroxymethylimidazole. Such processes are not claimed herein.
Japanese Patent Application 03/169865 describes the preparation of a wide variety of imidazoles using ammonia or an ammonium carbonate as the ammonia source. There is no recognition of the particular use of an ammonium carbonate in the presence of selected amines as described herein.